My '02 Pontiac Sunfire has an electrical issue. The battery is constantly dying. It will hold a charge after being boosted for about two weeks, after which the starter won’t even click. I drive the car rarely enough that I’m not sure how long it takes for the battery to die.
What could be causing such a problem? I’m hoping it can be fixed by replacing the battery, but I’m concerned it’s something more sinister like a constant drain on the battery due to some corroded wire. Is there an easy way to test what the problem could be?
Sounds like a bad alternator.
When you say “holds a charge” do you mean that you can drive the car for two weeks, or just let it sit for two weeks? If you are driving it, then the battery is not getting charged correctly, which implies a bad alternator or voltage regulator.
Could be the battery, could be the alternator, could be a gizmo draining the battery (trunk light, hood light, glove box light, radio, etc.). You don’t have enough data to tell. However, any competent service department has test equipment to narrow down the possibilities. You can probably find someone who will do an electrical check for free, in hopes of you buying parts and/ or service from them.
The way to troubleshoot this yourself involves a VOM (volt-ohm-meter) with ability to measure DC current up to a few amperes.
Starting with a charged battery, you pull one fuse at a time and place the meter leads across the open fuse terminals. If that circuit is not drawing electricity, the reading will be zero. When you find the circuit which is drawing current, troubleshoot further to resolve the issue.